In 2004, Michigan voters approved an amendment to the state’s constitution that defined marriage as being between one man and one woman. Michigan’s Supreme Court ruled 5-2 on Wednesday that the amendment applied to employee benefits offered by public entities. As such, same-sex domestic partners their children are not eligible to receive the benefits.

According to the Detroit Free Press, “Specifically, the court found that language in the amendment prohibiting recognition of other unions ‘for any purpose’ effectively bans same-sex partner benefits.”

Gay rights advocates in other states believe Michigan’s ruling could be felt in other states.

“The State Supreme Court of Michigan should be ashamed,” wrote a blogger known as the Snarling Marmot, who is worried about the ruling’s implications in Missouri.

Most entities affected by the Michigan Supreme Court ruling had already changed their policies to keep domestic partners covered by allowing an employee to cover “a designated beneficiary,” according to the Detroit Free Press.

Rick Hills, a Notre Dame Law professor and co-counsel for the Michigan case plaintiffs, called the court’s decision “confused” on the blog Prawfsblawg. The majority said a public employer is recognizing the validity of same-sex partnerships when benefits are offered. Hills questions other instances: if two professors are domestic partners, can a university ask one not to vote on the other’s tenure? Though the professor would have a conflict of interest, the university couldn’t “recognize” it under the court’s ruling, he says.

“No one gets their knickers twisted if I buy dinner for a friend, why should they if I buy insurance for someone whether I’m sharing a bed with that person or not. Being able to share my benefits with whomever I choose in no way hurts marriage. It simply hurts people who need help with insurance.”

People who oppose a gay marriage ban proposal in Florida say Michigan’s ruling “should be a major, bright red warning sign to Florida voters. If you don’t want to take away existing protections and benefits, don’t vote for Amendment 2,” said Heddy Pena of Florida Red and Blue. On the other side, John Stemberger said Michigan’s language was broader than what’s being proposed in Florida.

Jim Burroway at the blog Box Turtle Bulletin said anti-gay marriage advocates in other states have said they aren’t after domestic benefits, but he knows better: “When anti-marriage activists tell you that their proposals have nothing to do with domestic partnerships, don’t believe it. They said that in Michigan also.”

In a dissent, justices Marilyn Kelly and Michael Cavanagh wrote, “It is a perversion of the amendment’s language to conclude that, by voluntarily offering the benefits at issue, a public employer recognizes a union similar to marriage.” The entire decision and dissent is available in PDF.

The National Conference of State Legislatures has a timeline of same-sex marriage laws and rulings that starts with Massachusetts in 2003. Another page summarizes states’ domestic partner and civil union laws, and another lists states with some sort of legislation defending marriage.